1. Field of the Invention
The present invention generally relates to a light-emitting diode (LED) package, in particular, to an LED package with a carrier having heat dissipation and optical condensing or optical diffusing functions.
2. Description of Related Art
As the luminous efficiency of light emitting diodes (LEDs) is increasingly improved, LEDs have replaced fluorescent lamps and incandescent lamps in some fields, for example, lamp sources of scanners requiring for quick response, backlight sources or front light sources of liquid crystal displays (LCDs), illumination for dashboards of automobiles, traffic lights, and common illumination devices. Compared with conventional lamps, the LEDs have absolute advantages, for example, small volume, long lifespan, low driving voltage/current, non-fragile, mercury free (no pollution), and good luminous efficiency (power saving).
However, since the optical field of a single LED is linearly emitted at a small angle substantially, the optical field pattern of a plurality of LED light sources disposed in arrays on a plane substrate generally does not meet the requirements on various applications. Therefore, according to the requirements of applications, generally, an optical lens must be added on the optical path to condense or diffuse light beams. However, the optical lens may cause secondary optical effects, such as reflection, refraction, and absorption, thus reducing the efficiency of the optical transmission. Further, the optical lens is generally sealed on the substrate hermetically, and thus the gas is remained between the optical lens and the substrate, and thus the dissipation of the heat energy generated by the LED during operation may be blocked to the outside.
Since the poor heat dissipation effect is unsatisfactory, the temperature of the LED cannot be effectively lowered, which further affects the luminous efficiency and the life time of LED lamps.